Suture anchor for soft tissue fixation

ABSTRACT

A method and apparatus for anchoring suture to bone includes an anchor formed by twisting a wire to provide a loop with two legs extending distally from the twist. Each leg bends outwardly through 180° to define respective knee segments between inner and outer leg segments, the outer leg segments terminating in sharp points for penetrating a bone tunnel wall. The outer leg segments are initially parallel and define an anchor width smaller than the bone tunnel diameter, thereby permitting the anchor to be inserted into and removed from the tunnel. The anchor is deployed with an insertion tool arranged to deformably pivot the outer leg segments about the knee segments, thereby causing the pointed ends to penetrate the tunnel wall in response to applied withdrawal forces. The anchor wire may be assembled on an anchor sleeve through which the loop projects proximally while the outer leg segments reside in wire relief recesses defined in the sleeve periphery. The insertion tool selectively forces the sleeve against the inside of the knee segments while engaging the loop to thereby deformably pivot the outer leg segments. The insertion tool may include resiliently spaced jaws for engaging the wire loop, the jaws being disposed at the distal end of a rod selectively retractable into a tube to force the jaws closed. Further retraction of the rod applies the axial force for bending the wire legs.

CROSS REFERENCE TO RELATED APPLICATION

This application is a division of U.S. patent application Ser. No.08/078,907, filed Jun. 18, 1993 now U.S. Pat. No. 5,372,604 and entitled"Suture Anchor for Soft Tissue Fixation".

BACKGROUND OF THE INVENTION

1. Technical Field

This invention pertains to methods and apparatus utilized in surgicalprocedures involving fixation of soft tissue to bone tissue and, moreparticularly, to a novel method and apparatus for anchoring sutures tobone tissue to permit the aforesaid fixation.

2. Discussion of the Prior Art

As part of various endoscopic or arthroscopic surgical procedures, it isnecessary to permanently attach a suture to bone tissue. For example, incertain procedures requiring suturing of soft tissue (e.g., muscle,cartilage, tendons, ligaments, etc.) to bone tissue, the suture must beanchored to the bone tissue before suturing can proceed. The prior artincludes numerous suture anchors adapted to be secured in pre-drilledholes or tunnels in the bone tissue, and most of these anchors have oneor more disadvantageous characteristics. Some prior art suture anchorsare required to be hammered into the bone tunnel. These anchors areexemplified by U.S. Pat. Nos. 5,102,421 (Anspach, Jr.); 5,141,520 (Gobleet al); and 5,100,417 (Cerier et al). Hammering (or impacting as it isoften described) has the disadvantage of potential trauma and damage tosurrounding bone tissue, and has limited applicability where thelocation of the bone tunnel is not axially aligned with an arthroscopicportal to permit transmission of the impacting force through an impactorto the anchor.

Some suture anchors are threadedly mounted in the bone tunnel, asexemplified by U.S. Pat. Nos. 5,156,616 (Meadows et al) and 4,632,100(Somers et al). The screw insertion procedure tends to be time-consumingin that a pilot hole must first be drilled into the bone and then thehole may have to be tapped to receive the screw.

Many suture anchors involve an insertion procedure wherein the inserterdevice must partially enter the bone tunnel, thereby requiring a largerdiameter tunnel than would be necessary for the anchor alone. Examplesof such suture anchors are found in U.S. Pat. Nos. 5,037,422 (Hayhurstet al); 4,741,330 (Hayhurst); 4,968,315 (Gatturna) and 4,899,743(Nicholson et al).

Most of the foregoing exemplar prior art suture anchors suffer from thedisadvantage of being automatically deployed upon initial insertion intothe bone tunnel. Specifically, such anchors typically have permanentlyprojecting barbs, or the like, that are forced into the tunnel duringinitial insertion and preclude proximally directed movement in thetunnel after at least one barb engages the surrounding bone tissue. Itsometimes happens that a particular tunnel turns out to be unsuitable,either because of location or configuration, but the surgeon does notrecognize this until after the anchor has been inserted. With most priorart anchors there is no possibility of removing the inserted anchor;thus, a new tunnel must be drilled and a second anchor inserted.Accordingly, two (or possibly more) anchors may be left at the surgicalsite, only one of which is functional. This problem is addressed in U.S.Pat. No. 5,176,682 (Chow) wherein a suture anchor is disclosed as havingnormally retracted fins capable of being selectively projected radiallyto engage the bone tunnel walls in a barb-like manner. Selectiveprojection of the fins is effected by hammering a pin axially throughthe anchor to force the fins radially outward. Prior to hammering thepin, the inserted anchor is readily removable from the bone tunnel,thereby permitting the surgeon to test the adequacy of the drilledtunnel and its location. If the tunnel is unsatisfactory, the anchor canbe removed, rather than being left in place. Although this techniquesolves the problem of having an unused anchor left in an unsatisfactorytunnel, it has some other disadvantages. Specifically, permanentinstallation of the anchor requires tools (i.e., a hammer and impactor)that are separate and apart from the inserter. Additionally, duringimpacting, the pin may be inadvertently driven entirely through theanchor and thereby damage bone tissue at the closed end of the tunnel.

OBJECTS AND SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide improvedmethods and apparatus for anchoring suture to bone.

It is another object of the invention to provide a suture anchor capableof being temporarily inserted into a bone tunnel to determine thedesirability of the site, and then easily actuated for permanentdeployment.

A further object of the invention is to provide a suture anchor that canbe inserted and positively engaged in a bone tunnel without requiringhammering of the anchor or threading the tunnel.

It is yet another object of the present invention to provide a methodand apparatus for securing a suture anchor in a bone tunnel withoutrequiring the tunnel diameter to be larger than necessary to accommodatethe anchor.

In accordance with the present invention, a suture anchor wire isconfigured from a deformable wire bent to provide a loop at theapproximate center of the wire length. The loop constitutes the proximalend of the anchor. The wire is twisted to close off the loop at a twistjuncture from which two legs extend generally distally and then bendaway from one another through approximately 180° each to extend in aproximal direction along opposite transverse sides of the anchor. Endsof the wire are cut on a bias to define sharp points at the outertransverse sides of the leg ends. The 180° bend in each leg forms aU-shaped knee dividing the leg into substantially parallel inner andouter leg segments.

An anchor insertion tool includes an elongated hollow outer tube and aninner tube telescopically movable therein. Jaws at the distal end of theinner tube include one or more projections configured to permit theanchor wire loop to be selectively engaged between the jaws. With theanchor engaged, a generally annular actuator edge of the outer tube ofthe inserter tool, or of a sleeve disposed about the inner tube andextending forwardly of the outer tube, is axially spaced from the anchorwire legs. The actuator edge has an outside diameter made smaller thanthe transverse spacing between the outward sides of the outer legsegments, but larger than the transverse spacing between the inwardsides of the outer leg segments. Suture or similar material can belooped about the twist between the two inner leg segments of the anchorwire and pulled back proximally before the engaged anchor is insertedinto a pre-drilled tunnel in bone tissue. The transverse spacing betweenthe proximally-directed anchor leg segments permits the anchor to bemoved freely into and out of the tunnel. When the anchor wire ispositioned as desired, the actuator inner tube is retracted into theouter tube, thereby causing the actuator edge to move distally relativeto the anchor wire and into the space between the leg segments of eachwire leg. As the actuator edge moves between the leg segments it forcesthe outer segments outwardly, thereby deforming the wire knee so thatthe pointed ends of the outer segments engage the wall in the bonetunnel. The entire tool can then be pulled in the proximal direction,with the anchor loop still engaged by the actuator, to cause the pointedends of the now outwardly bent outer leg segments of the anchor tofirmly engage the wall of the tunnel. Disengagement of the inserter toolfrom the anchor wire is effected by opening the jaws of the inner tubeto disengage the wire loop. The tool can then be removed from thesurgical site and the suture remains in the bone tunnel, firmly engagedabout the anchor wire twist.

In one embodiment, the anchor also includes a sleeve on which the anchorwire, as described above, is mounted. The anchor sleeve has an opendistal end and a proximal end wall having a central opening. The wire ismounted with its loop protruding rearwardly through the hole in theproximal end wall, and with its U-shaped knee bent over the edge of theopen distal sleeve end. Recessed channels extend longitudinally alongthe outside of the sleeve from its distal end to receive the outer legsegments of the anchor wire. When thusly received, the entire diametricthickness of the outer leg segment is recessed in the channel. As in thefirst described embodiment, the rearward projecting wire loop isengageable between the jaws of the insertion tool. During deployment,instead of spreading the outer leg segments directly by means of thedistal end of the insertion tool outer tube, the distal end of the tubeis forced against the proximal end wall of the anchor sleeve. Thesleeve, in turn, is thusly movable distally relative to the engagedanchor wire to force the outer leg segments of the wire radiallyoutward. In this embodiment the anchor sleeve remains in the bone tunnelalong with the anchor wire after deployment.

These and other objects, features and many of the attendant advantagesof the present invention will be appreciated more readily as they becomebetter understood from a reading of the following description consideredin connection with the accompanying drawings wherein like parts in eachof the several figures are identified by the same reference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view in plan of an anchor wire constructed in accordancewith one embodiment of the present invention.

FIG. 2 is a side view, partly broken, of an inserter tool utilized inconnection with the anchor wire according to the present inventionshowing the tool in its deployment position.

FIG. 3 is a side view, partly broken, of the inserter tool shown in itspre-deployment position.

FIG. 4 is a top view in plan of the combination of the anchor wire ofFIG. 1 and the distal end of the insertion tool of FIG. 2, thecombination being shown prior to engagement of the anchor wire.

FIG. 5 is a side view in elevation of the distal end of the insertiontool taken along lines 5--5 of FIG. 4.

FIG. 6 is a top view in plan of the anchor wire and the distal end ofthe insertion tool showing the anchor wire engaged prior to deploymentand the inner tube of the insertion tool fully extended.

FIG. 7 is a top view in plan of the anchor wire and the distal end ofthe insertion tool showing the anchor wire in its inserted butnon-deployed position and the inner tube of the insertion tool partiallyretracted.

FIG. 8 is a top view in plan of the anchor wire and the distal end ofthe insertion tool showing the anchor wire fully deployed and the innertube of the insertion tool fully retracted.

FIG. 9 is a top view in plan of the anchor wire during as it appearsprior to insertion into a bone tunnel and showing a suture engaged bythe anchor wire.

FIG. 10 is a top view in plan of the anchor wire fully deployed in abone tunnel and showing a suture engaged by the anchor wire and retainedin the bone tunnel.

FIG. 11 is a view in perspective of a second embodiment of the anchor ofthe present invention utilizing an anchor sleeve in combination with theanchor wire, and an insertion tool for engaging the anchor wire.

FIG. 12 is an exploded view in perspective of the anchor wire and anchorsleeve of FIG. 11.

FIG. 13 is a distal end view in elevation of the anchor sleeve.

FIG. 14 is a view in section taken along lines 14--14 of FIG. 13.

FIG. 15 is a view in section taken along lines 15--15 of FIG. 13.

FIG. 16 is a view in perspective of the insertion tool of FIG. 11.

FIG. 17 is a side view in elevation of the anchor assembly of FIG. 11engaged by the insertion tool immediately prior to insertion into a bonetunnel.

FIG. 18 is a side view in elevation of the anchor assembly of FIG. 11and the insertion tool showing the anchor assembly partially insertedinto a bone tunnel.

FIG. 19 is a view in plan of another anchor wire embodiment of thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring specifically to FIG. 1, an anchor wire 10 is bent and twistedto provide an engagement loop 11 positioned approximately at the centerof the length of the wire. Engagement loop 11 constitutes the proximalend of the anchor device and, in the preferred embodiment, has agenerally elliptical configuration with its major axis extendinglongitudinally. The forward end of loop 11 terminates in a twist 13formed in wire 10, the preferred twist being 180° about the longitudinalaxis of the anchor to close off the loop from the distal end of theanchor. Specifically, each leg of the wire bends through approximately90° to form twist 13. Extending forwardly from twist 13 are two legs,each having a 180° outward bend or knee 17, 23 to separate inner andouter leg segments. Specifically, one leg includes an inner segment 15extending forwardly from twist 13 to knee 17, and an outer segment 19extending rearwardly from knee 17 and substantially parallel to innersegment 15. Outer segment 19 constitutes the radially outwardmost partof one side of the anchor wire and terminates in a pointed end 20 formedby cutting the wire end on a bias in a proximal and outward direction.The other leg is a substantially mirror image (about the anchorlongitudinal axis) of the first leg and has corresponding inner segment21, knee 23, outer segment 25 and pointed end 27. The forward ends ofknees 17 and 23 are longitudinally coextensive and define the distal endof the anchor wire.

Anchor wire 10 is preferably a metal wire, typically stainless steel,that is bendable but not significantly resilient. Accordingly, if, inthe manner described below, outer leg segments 19 and 25 are bentoutwardly about respective knees 17 and 23 to form some angle other than180° with the inner segments 15 and 21, the resulting deformation of theanchor wire remains set after the bending force is removed.

In an exemplar embodiment of anchor wire 10, the wire has a roundtransverse cross-section with a diameter of 0.015". The overall length(i.e., from the proximal end of loop 11 to the distal ends of knees 17,23) of the formed anchor wire is 0.220", with the outer leg segmentseach occupying 0.100" of that length. The maximum transverse width ofthe anchor wire between the outermost parts of outer leg segments 19 and25 is 0.110". The transverse space between inner leg segments 15 and 21is 0.030". Likewise, the transverse space between the long sides of loop11 is 0.030". The angle of the bias cut in outer leg segments 19 and 25to form respective points 20 and 27 is 30°. Again, it is to be notedthat these dimensions are for purposes of example only and are notlimiting on the scope of the present invention.

An anchor insertion tool 30 is illustrated in FIGS. 2 and 3 includesconcentric inner and outer tubes 31 and 33, respectively. Outer tube 33is fixedly secured to and extends forwardly from an actuator housing 35.A thumb-engaging handle arm 37 is fixedly secured to the proximal end ofhousing 35, extending rearwardly and transversely therefrom andterminating in a thumb-receiving loop 39. A finger-engaging handle arm40 is pivotably secured within housing 35 and extends transverselyforwardly therefrom to form an acute angle with arm 37. Afinger-receiving loop 41 terminates the free end of arm 40. In aconventional manner, arm 40 is linked within housing 35 to the proximalend of inner tube 31 such that forward movement of arm 40 relative toarm 37 (i.e., increased angular separation) results in coaxially forwarddisplacement of inner tube 31 within outer tube 33. Likewise, rearwardmovement of arm 40 (i.e., decreasing the angular separation) causesinner tube 31 to move axially rearward within outer tube 33. In thismanner, the distal end of inner tube 31 may be selectively projectedbeyond the distal end of tube 33, or fully retracted within the outertube. The diameters and lengths of tubes 31, 33 are such to permit theirdistal ends to be inserted through an endoscopic surgical portal andpositioned at a surgical site. The particular embodiment illustratedherein is best suited for arthroscopic procedures.

The distal end of inner tube 31 terminates in a pair of resilientlyspaced jaws 43 and 45. When inner tube 31 is fully extended forwardly,jaws 43 and 45 are exposed and maximally separated. In this position thespacing between the outside surfaces of the jaws exceeds the innerdiameter of outer tube 33. As the inner tube is retracted into the outertube, the interior wall of outer tube 33 serves as a cam to graduallyurge jaws 43 and 45 together in opposition to their resilient separationbias. The interior or mutually facing surfaces of jaws 43 and 45 haverespective engagement pins 44 and 46 projecting inwardly toward oneanother. In the fully open position of the jaws (i.e., in the fullyextended position of inner tube 31), the spacing between engagement pins44 and 46 is at least equal to the diameter of the wire used for anchorwire 10. The cross-sectional shape of pins 44 and 46 (i.e., transverselyof their mutual projection directions) is chosen to permit the pins tofit into the loop 11 of the anchor wire when the jaws are closed.Preferably, the engagement pins are cylinders having a radius equal toor just slightly smaller than the radius of curvature of the proximalend of the interior portion of wire loop 11.

Referring to FIGS. 4 and 5, when it is desired to load anchor wire 10onto insertion tool 30, inner tube 31 is extended to its most distalposition relative to the outer tube by angularly separating handle arms37 and 40 to their maximum separation. Jaws 43 and 45 are resilientlyspread and pins 44 and 46 thereby are spaced from one another. Theanchor wire loop may then be inserted between jaws 43, 45 and theirengagement pins 44, 46. As illustrated in FIG. 6, the jaws may beclosed, bringing engagement pins 44, 46 into contact through anchor wireloop 11. Closure of the jaws is effected by pivoting handle arm 40partway toward handle arm 37, thereby causing partial retraction ofinner tube 31 into outer tube 33. This retraction, in turn, causes thedistal edge of the outer tube to force jaws 43 and 45 together inopposition to their resilient separation bias.

To ready the anchor wire for insertion into a bone tunnel, inner tube 31is further retracted into outer tube 33, as illustrated in FIGS. 7 and9, until the loaded anchor wire is disposed with the proximal end ofloop 11 abutting the distal end of outer tube 33. In this position, asuture 50 can be disposed with an intermediate portion of its lengthbetween inner leg segments 15 and 21 and at the distal end of wire twistjunction 13. The two ends of suture 50 are pulled rearwardly to extendalong the outer tube 33 of the insertion tool. Suture 50 and the anchorwire 10, engaged by the insertion tool, can then be inserted into apredrilled bone tunnel 51. The bone tunnel diameter is substantiallyequal to or slightly larger than the maximum transverse spacing betweenthe outer edges of outer legs segments 19 and 25 to readily permitinsertion of the entire anchor wire and the distal end of the insertiontool into the bone tunnel. With the anchor wire thusly inserted in thetunnel, the surgeon can determine whether or not the tunnel and itslocation are satisfactory for the contemplated soft tissue anchoringprocedure. If the bone tunnel is not satisfactory, the insertion tooland the engaged anchor wire may be readily withdrawn from the tunnel andinserted into a new tunnel appropriately drilled and positioned.

If the bone tunnel is determined to be satisfactory for the contemplatedprocedure, the anchor wire may be permanently deployed. In particular,and as illustrated in FIGS. 8 and 10, the outer leg segments 19, 25 ofthe inserted anchor wire are forced outwardly by fully retracting innertube 31 into outer tube 33 while pulling rearwardly on the insertiontool and, in turn, on the engaged anchor wire. As the inner tube isretracted, the interior sides of knees 17 and 23 move axially toward thedistal edge of outer tube 33. The outer tube end begins wedging betweeninner leg segment 15 and outer leg segment 19, and between inner legsegment 21 and outer leg segment 25, thereby causing the outer legsegments to bend outwardly about their respective knees. Pointed wireends 20 and 27 diverge by virtue of this bending and dig into the wallof the bone tunnel as the assembly is pulled in a rearward direction.When sufficient resistance to rearward movement is encountered, theanchor wire is deemed properly implanted and the insertion tool can bedisengaged from the anchor wire loop 11. This disengagement is effectedby moving inner tube 31 proximally to permit jaws 43 and 45 toresiliently separate and release wire loop 11. The insertion tool maythen be fully withdrawn from the surgical site, leaving the anchor wirefirmly positioned within the bone tunnel and suture 50 looped around theanchor wire. The 180° twist 13 in the anchor wire prevents the suturefrom being drawn into loop 11 when the ends of the suture are pulled toachieve desired tension.

It is to be noted that, although the preferred embodiment of theinsertion tool includes respective engagement pins secured to the jaws43 and 45, other jaw configurations are possible and fall within thescope of the present invention. For example, only one of the jaws mayhave a projecting pin configured to engage the opposing jaw when thejaws are closed. Alternatively, the opposing jaw may have a recess orbore defined therethrough in position to receive the engagement pin fromthe first-mentioned jaw. The configurations of the engagement pins neednot be cylindrical; rather, any configuration capable of serving thefunctions described above is appropriate for the engagement pins.

Likewise, the specific manner by which the jaws are opened and closedshould not be a limiting feature of the invention. In particular, thepreferred insertion tool described above effects closure of the jaws bywithdrawing the resiliently spaced jaws into an outer tube. Rather thanproviding the illustrated inner tube and outer tube combination, asingle tube may be provided with nonresilient jaws formed at its distalend. One of the jaws would be pivotable relative to the tubes so as toselectively close the jaws in a manner similar to that employed forarthroscopic graspers and cutters well known in the prior art. An outersleeve may then be disposed over the distal end of the insertion tool tobe selectively axially movable relative to the jaws to bend the outerleg segments of the anchor wire in a manner described.

An alternative embodiment of the anchor assembly and insertion tool areillustrated in FIGS. 11-18 to which specific reference is now made. Inthis embodiment the anchor assembly includes anchor wire 10, configuredas described above, and a biocompatable anchor sleeve 60. The anchorsleeve 60 has a generally cylindrical configuration with a proximal endwall 61 having a central hole or opening 63 defined therethrough. Thediameter of hole 60 is sufficient to permit loop 11 of the anchor wireto project proximally therethrough when the anchor wire is received insleeve 60 in the manner described below. The opposite or distal end 65of sleeve 60 is open to receive the anchor wire. Longitudinallyextending wire relief channels or recesses 67, 69 are defined in theouter surface of sleeve 60 and extend along the entire length of thesleeve. Channels 67 and 69 are disposed at 180°-spaced locations aboutthe sleeve circumference and are sufficiently deep to receive most, ifnot all, of the diametric thickness of respective outer leg segments 19and 25. That is, anchor wire 10, when received in sleeve 60, has theinside surfaces of its knees 17 and 23 disposed in abutting relationwith the distal edge of the sleeve. Further, the natural spacing betweenthe outermost edges of inner leg segments 15 and 21 is greater than theinner diameter of sleeve 60. Accordingly, sleeve 60 is retained onanchor wire 10 by a forced fit created by the limited resilience of theanchor wire. In the preferred embodiment, distal end 65 has a pair ofrecesses 66, 68 serving as extensions of respective channels 67, 69 toreceive the entire thickness of respective knees 17 and 23. In thisreceived position of the anchor wire, inner leg segments 15, 21 andtwist junction 13 are disposed inside sleeve 60.

At two 180°-spaced locations, spaced 90° from wire relief channels 67and 69, the wall of sleeve 60 is completely removed along the entiresleeve length. The resulting open spaces 71, 73 are continued asrespective arcuate recesses 75, 77 defined in the circumferential edgeof proximal end wall 61. Spaces 71, 73 serve as suture relief spacesthrough which suture 50 extends when looped about the proximal end ofwire twist 13 between inner leg segments 15 and 21.

The insertion tool 80 employed with the anchor assembly of wire 10 andsleeve 60 may be substantially the same tool described above. As shownin FIGS. 11-18, the outer tube 33' of the tool may have a pair of180°-spaced slots 81, 83 cut through the entire tube wall thickness andextending a short distance rearward from the outer tube distal end. Thesuture ends thus extend through spaces 71, 73 and recesses 75, 77 toreside along the slots 81 and 83.

The operation of the anchor assembly of FIGS. 11-18 is similar to thatdescribed above in relation to FIGS. 1-10. Anchor wire loop 11, exposedthrough sleeve hole 63, is engaged in the same manner between jaws 43and 45, and the sequence of deployment proceeds as previously describedwith two significant exceptions. First, instead of the outer legsegments 19 and 25 being deformably bent directly by the distal end ofthe outer tube 33' upon retraction of the inner tube, the outer tubedistal end urges sleeve 60 forwardly relative to the anchor wire. Thedistal end of the sleeve thus deformably bends the outer leg segments ofthe wire outwardly under the urging of the distal end of the outer tubeas the inner tube retracts.

A second significant distinction resides in the fact that biocompatablesleeve 60 may remain deployed with the anchor wire in the bone tunnel.The forced fit between the sleeve and the inner leg segments 15 and 21assures that the sleeve will not become disengaged. Of course, thesleeve can be designed to be removed after deployment of the wire, ifdesired.

Sleeve 60 is made of any suitable bio-compatible metal or plasticmaterial. In an exemplar embodiment, the sleeve has a length of 0.157"and an outside diameter of 0.100". Hole 63 in proximal end wall 61 has adiameter of 0.060" which is substantially equal to the maximumtransverse dimension of anchor wire loop 11. Channels 67 and 69 aregenerally semi-cylindrical with a depth of 0.015", while spaces 71, 73each subtend a circumferential angle on the order of 60°. The transversespace between interior walls across spaces 71, 73 is 0.040".

It may be desirable, in some instances, to configure the anchor wire inthe manner illustrated in FIG. 19 wherein anchor wire 10' is configuredto have its pointed ends 20', 27' curved outwardly and way from thelongitudinal axis of the anchor. This curvature at the tips of theanchor facilitates penetration into the bone upon outward bending ofouter segments 19 and 25 during deployment. In all other respects anchorwire 10' is substantially the same as anchor wire 10.

It will be understood that some of the specific details of the exemplaryembodiments described above are not limiting on the scope of theinvention. In particular, the feature of primary importance in theanchor is the presence of two or more wire legs capable of beingdeformably bent outward while in a bone tunnel to permit their pointedends to penetrate the bone tunnel wall upon being pulled proximallytoward the tunnel opening. On the other hand, prior to being bent, thewire legs are retracted such that the maximum transverse dimension ofthe anchor permits it to be readily inserted into and removed from thetunnel. In this regard, the anchor may comprise only the wire, or thewire engaged by a biocompatable anchor sleeve (both as described above);or it may comprise a body of biocompatable metal or plastic materialhaving the bendable pointed legs embedded therein or otherwise securedat the distal end of the body, and with a loop or other anchorengagement structure at the proximal end of the body. The configurationof the anchor body is not, of itself, critical to the invention,although certain configurations, such as those described herein, aremore advantageous than others. The key features, again, are the factthat the legs are deformable to effect deployment while the anchor is inthe bone tunnel to permit the anchor to be removed after insertion butprior to bending for deployment, a passage for engaging a suture loopedabout or through the anchor, and a mechanism for engaging the anchorwith a removable insertion tool capable of selectively deploying theanchor in the tunnel by causing the legs to deformably bend outwardlywithout hammering or impacting the anchor. The specific insertion toolconfigurations described herein, although particularly advantageous, canalso be varied within the scope of the invention. The key features ofthe tool are the capability of engaging the anchor for selectiveinsertion into and removal from the bone tunnel, and the capability ofselectively deploying the anchor by causing deformation of the anchorlegs. It should also be noted that inner tube 31 of the illustratedinsertion tool may be any rod-like member, whether or not tubular.

From the foregoing description it will be appreciated that the inventionmakes available a novel suture anchor for soft tissue fixationcharacterized by being removable from a bone tunnel after insertion butbefore deployment, easily actuated for permanent deployment, anddeployable without requiring hammering of the anchor suture or threadingof the bone tunnel.

In accordance with the present invention, it is believed that othermodifications, variations and changes will be suggested to those skilledin the art in view of the teachings set forth herein. It is thereforeunderstood that all such variations, modifications and changes arebelieved to fall within the scope of the present invention as defined bythe appended claims.

What is claimed is:
 1. In combination:a bone anchor for securing suturein a bone tunnel by engaging the bone tunnel wall, said anchorcomprising:a body section; at least first and second bendably deformablewire legs having no significant resilience, each leg having a first endsecured to said body section and an opposite end suitable forpenetrating bone tissue; an engageable element projecting from said bodysection to permit the anchor to be grasped and positioned in the bonetunnel;wherein said anchor has a pre-deployment position in which saiddeformable wire legs are retracted in a dimension transversely of thebone tunnel axis to permit the anchor to be unimpededly inserted intoand removed from the bone tunnel; and wherein said anchor, while in thebone tunnel, is capable of being deformably bent to a permanentdeployment position in which said wire legs extend generally toward anopening of the bone tunnel at an acute angle to the bone tunnel wall topermit the pointed ends of the wire legs to penetrate the bone tunnelwall as the anchor is moved in a direction toward the tunnel opening;and an insertion tool comprising:an elongated rod having a distal endand a proximal end; selectively openable and closeable jaws disposed atsaid distal end of said rod, said jaws being configured to firmly engagesaid engageable element when closed; an actuator disposed at theproximal end of said rod for permitting manually actuated opening andclosing of said jaws; and a member mounted on said tool to beselectively movable longitudinally relative to said rod, said memberhaving a distalmost position relative to said rod wherein said membercauses said wire legs to deformably bend outwardly to said permanentdeployment position.
 2. The combination of claim 1 wherein said rod isbifurcated at its distal end to define said two resiliently spaced rodends constituting said jaws;wherein said member comprises an outer tubedisposed about said rod and having an open distal end and an innerdiameter smaller than the resiliently spaced jaws; and wherein said tubeand rod have a first position with said jaws projecting maximally beyondthe distal end of said tube, and a second position with the rod moreretracted into the tube to thereby force the jaws to close.
 3. Thecombination of claim 2 wherein said tube has a proximal end fixedlysecured to said actuator, and wherein said actuator includes means forselectively moving said rod distally and proximally within said tube. 4.The combination of claim 2 wherein said tube has a proximal end fixedlysecured to said actuator, and wherein said actuator includes means forselectively moving said rod distally and proximally within said tube. 5.The combination of claim 3 wherein said anchor further comprises:abendable wire having a twist section therein to define a loop at alocation intermediate said first and second ends, said loop defining aproximal end of said anchor, said twist constituting at least part ofsaid body section; said wire further comprising said first and secondlegs each having:an inner leg segment extending generally distally fromsaid twist section; a knee section in the form of a 180°-outward bendextending from the distal end of said inner leg segments; and an outerleg segment extending proximally from said knee segment and terminatingin said pointed end;wherein, in said pre-deployment position, said kneesegment is a bend through an angle of approximately 180°, and whereinfor said deployment position said outer leg segments are; wherein saidjaws of said insertion tool are configured to firmly engage said loopwhen said jaws are closed; and wherein said member on said tool in saiddistalmost position causes said outer leg segments to deformably pivotoutwardly about said knee segments.
 6. The combination of claim 5wherein said rod is bifurcated at its distal end to define said tworesiliently spaced rod ends constituting said jaws;wherein said membercomprises an outer tube disposed about said rod and having an opendistal end and an inner diameter smaller than the resiliently spacedjaws; and wherein said tube and rod have a first position with said jawsprojecting maximally beyond the distal end of said tube, and a secondposition with the rod more retracted into the tube to thereby force thejaws to close.
 7. The combination of claim 5 wherein said wire loop hasa substantially elliptical configuration with a major axis extendinglongitudinally of said anchor, wherein the proximal end of said loop hasa predetermined inside radius of curvature, and wherein at least one ofsaid jaws includes a cylindrical pin extending toward the other of saidjaws and having a radius contoured to match said predetermined radius ofcurvature.